Robot cleaner

ABSTRACT

A robot cleaner includes a first cleaning module including left and right spin mops configured to rotate clockwise or counterclockwise when viewed from above while being in contact with a floor, and a second cleaning module including a rolling member configured to rotate clockwise or counterclockwise when viewed from a left side while being in contact with a floor, the rolling member being spaced apart from the left and right spin mops in an anteroposterior direction. A controller controls rotational motion of the left and right spin mops and rotational motion of the rolling member.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Phase entry under 35 U.S.C. § 371 from PCT International Application No. PCT/KR2017/007561, filed Jul. 14, 2017, which claims the benefit of priority of U.S. Provisional Application No. 62/362,358, filed Jul. 14, 2016, the contents of which are incorporated herein by reference in their entireties.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a robot cleaner capable of performing a mopping operation and a method of controlling the same.

2. Description of the Related Art

A robot cleaner is an apparatus that cleans a floor by suctioning foreign matter, such as dust, from the floor or sweeping away foreign matter on the floor while traveling autonomously. In recent years, there have been developed robot cleaners capable of performing a mopping operation.

Korean Registered Patent Publication No. 10-1602790 (Conventional Art) discloses a robot cleaner capable of traveling using a mop. In Conventional Art, the robot cleaner is configured such that a first rotary member and a second rotary member for fixing a pair of mops disposed in the leftward-rightward direction are inclined downwards and outwards from vertical shafts thereof. In the robot cleaner disclosed in Conventional Art, the first rotary member and the second rotary member are rotated to move the robot cleaner in the state in which only the mops fixed to the first rotary member and the second rotary member are in contact with a floor.

Conventional Art, which discloses the robot cleaner configured to travel through the rotation of the mops disposed in the leftward-rightward direction, has a problem in that frictional forces generated between the rotating mops and the floor frequently change, whereby it is difficult for the robot cleaner to travel straight. If it is difficult for the robot cleaner to travel straight, a considerable portion of the floor near a wall, along which straight travel of the robot cleaner is required, may not be cleaned with the mops.

Furthermore, the robot cleaner according to Conventional Art, which is configured to move using the surfaces of a pair of left and right mops, has a problem in that the traveling speed and trajectory are restricted.

In addition, the robot cleaner according to Conventional Art, which is configured to move using the surfaces of the pair of left and right mops, has a problem in that it is difficult to perform a mopping operation without rotational motion in place or straight motion.

DISCLOSURE Technical Problem

Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a robot cleaner capable of performing a stable traveling operation.

Another object of the present invention is to provide a robot cleaner capable of traveling along various traveling trajectories at various traveling speeds.

Still another object of the present invention is to provide a robot cleaner capable of performing a mopping operation while standing in place.

A further object of the present invention is to provide a robot cleaner capable of performing a traveling operation suitable for the situation using various traveling motions.

Technical Solution

In accordance with an aspect of the present invention, the above and other objects can be accomplished by the provision of a robot cleaner including a first cleaning module including left and right spin mops configured to rotate clockwise or counterclockwise when viewed from above while being in contact with a floor, a second cleaning module including a rolling member configured to rotate clockwise or counterclockwise when viewed from a left side while being in contact with a floor, the rolling member being spaced apart from the left and right spin mops in an anteroposterior direction, and a controller for controlling rotational motion of the left and right spin mops and rotational motion of the rolling member, thereby realizing various traveling motions by combining rotational motion of the left and right spin mops with rotational motion of the rolling member.

Advantageous Effects

According to at least one of the embodiments of the present invention, there is an advantage in that the robot cleaner performs a stable traveling operation using the pair of spin mops and a single rolling mop.

According to at least one of the embodiments of the present invention, it is possible to realize various traveling motions by combining rotational motion of the left and right spin mops with rotational motion of the rolling mop.

According to at least one of the embodiments of the present invention, the robot cleaner is able to perform a traveling operation suitable for the situation using various traveling motions.

According to at least one of the embodiments of the present invention, the robot cleaner is able to perform a mopping operation while standing in place.

The robot cleaner and the method of controlling the robot cleaner according to the present invention are not limited to the above-described embodiments, and all or some of the above embodiments may be selectively combined so as to realize various modifications.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a robot cleaner according to an embodiment of the present invention;

FIG. 2 is a perspective view of the robot cleaner shown in FIG. 1, which is viewed at a different angle;

FIG. 3 is an elevation view of the robot cleaner shown in FIG. 1, which is viewed from the front;

FIG. 4 is a bottom view of the robot cleaner shown in FIG. 1;

FIG. 5a is a vertical cross-sectional view taken along line S1-S1′ of FIG. 4;

FIG. 5b is a vertical cross-sectional view taken along line S2-S2′ of FIG. 4;

FIG. 6 is a perspective view of the robot cleaner shown in FIG. 1, with a case removed therefrom;

FIG. 7 is a detailed perspective view illustrating a first cleaning module and a second cleaning module of the robot cleaner shown in FIG. 1;

FIG. 8 is a block diagram illustrating a control relationship among substantial components of the robot cleaner according to an embodiment of the present invention; and

FIGS. 9 to 22 are views useful for the description of a method of controlling various traveling operations of the robot cleaner according to the embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following description, the terms “forward,” “rearward,” “leftward,” “rightward,” “upward,” and “downward,” which indicate directions, are defined based on forward (F), rearward (R), leftward (Le), rightward (Ri), upward (U), and downward (D) directions as illustrated in the drawings. In this specification, the direction in which a display panel is positioned with respect to a backlight unit is defined as the forward direction, and the other directions are defined based on the forward direction. However, these definitions are given only for clear understanding of the present invention, and the directions may be defined differently depending on the circumstances.

In the following description, the terms “first,” and “second” are used only to avoid confusion between designated components, and do not indicate the sequence or importance of the components or the relationships between the components. For example, the present invention may be implemented using only a second component, without a first component.

The “mop” used herein may be formed of various materials, such as cloth or paper. The mop may be repeatedly used via washing or may be disposable.

The present invention may be applied to a manual cleaner, which is moved by a user, or a robot cleaner or the like, which is able to travel autonomously. Hereinafter, embodiments will be described based on a robot cleaner.

Referring to FIGS. 1 to 7, a robot cleaner 100 according to an embodiment of the present invention includes a body 110 having a controller 20. The robot cleaner 100 includes a first cleaning module 120 for supporting the body 110. The robot cleaner 100 includes a second cleaning module 130 for supporting the body 110. The body 110 is supported by the first cleaning module 120 and the second cleaning module 130.

The first cleaning module 120 is configured to perform a mopping operation while in contact with a floor. The first cleaning modules 120 includes a left spin mop 120 a and a right spin mop 120 b, which rotate clockwise or counterclockwise to perform a mopping operation, when viewed from above. The left spin mop 120 a and the right spin mop 120 b are configured to come into contact with a floor. The first cleaning module 120 is disposed at a low side of the body 110. The first cleaning module 120 is disposed in front of the second cleaning module 130. The robot cleaner 100 may be constructed such that the body 110 is movable by the rotational motion of the first cleaning module 120 without an additional wheel.

The first cleaning module 120 includes a pair of spin mop modules 120. The first cleaning module 120 includes a left spin mop module 120 having the left spin mop 120 a and a right spin mop module 120 having the right spin mop 120 b. The left spin mop module 120 and the right spin mop module 120 are configured to perform a mopping operation. Each of the left spin mop module 120 and the right spin mop module 120 includes a mop member 121, a rotating plate 122, a water supply receiver (not shown), a spin rotating shaft 128, a spin drive unit 124 and a drive transmission unit 127. Each of the left spin mop module 120 and the right spin mop module 120 includes a tilting frame 125, a tilting rotating shaft 126 and an elastic member 129. The components included in the first cleaning module 120 may be considered as the components included in each of the left spin mop module 120 and the right spin mop module 120.

The second cleaning module 130 is configured to come into contact with a floor. The second cleaning module 130 may be configured to come into contact with a floor so as to perform a mopping operation. The second cleaning module 130 is disposed below the body 110. The second cleaning module 130 may be disposed at a position anteroposteriorly spaced apart from the left and right spin mops 120 a and 120 b, and may come into contact with a floor. For example, the second cleaning module 130 is disposed behind the first cleaning module 120 so as to come into contact with a floor. In this embodiment, the second cleaning module 130 is configured to perform a mopping operation while rotating.

In another example, the second cleaning module 130 may include a mop pad and the like, which performs a mopping operation while sliding on a floor due to movement of the body 110.

In still another example, the second cleaning module 130 may be configured to be capable of performing a vacuum-cleaning operation.

In a further example, the second cleaning module 130 may include a brush for performing a sweeping operation on a floor. In this case, the brush may be configured to be capable of rotating.

Hereinafter, the present invention will be described with reference to this embodiment. Since the second cleaning module 130 can play its own role if the second cleaning module 130 supports the body while in contact with a floor, the specific construction of the second cleaning module 130 for cleaning may be modified.

The second cleaning module 130 may include a rolling member 130 a. The robot cleaner 100 may be configured such that the body 110 is movable by the rotational motion of the second cleaning module 130 without an additional wheel.

The rolling member 130 a may be configured to be rotated about a rotational axis different from those of the spin mops 120 a and 120 b.

For example, the rolling member 130 a may be configured to be rotated about a rotational axis extending substantially horizontally. Accordingly, the rolling member 130 a may be rotated clockwise or counterclockwise when viewed from the left or right side. The second cleaning module 130 may be configured to perform a mopping or sweeping operation while rotating clockwise or counterclockwise when viewed from one side (the left side or right side).

The rolling member 130 a may include a mop disposed on the outer surface thereof so as to perform a mopping operation or a brush disposed on the outer surface thereof so as to perform a sweeping operation. The mop or the brush may be fixedly coupled to the rolling member 130 a, or may be detachably coupled thereto.

Although an embodiment in which the second cleaning module 130 includes the rolling mop 130 a, that is, the rolling member 130 a including the mop, will be described hereinafter, the specific construction of the second cleaning module 130 for performing cleaning may be modified.

The robot cleaner 100 may be configured such that the body 110 is moved by rotational motion of at least one of the first cleaning module 120 and the second cleaning module 130 without an additional wheel. The body 110 may be moved only by the rotational motion of the first cleaning module 120. Furthermore, the body 110 may be moved only by the rotational motion of the second cleaning module 130. The body may be moved by the rotational motion of the first cleaning module 120 and the rotational motion of the second cleaning module 130.

The robot cleaner 100 includes a water supply module (not shown) for supplying water required for a mopping operation. The water supply module may supply water required for a mopping operation of the first cleaning module 120 or the second cleaning module 130. In this embodiment, the water supply module supplies water the first cleaning module 120. The water supply module supplies water to the left spin mop module 120 and the right spin mop module 120.

The water supply module includes a water tank (not shown) for storing water to be supplied to the first cleaning module 120 or the second cleaning module 130. In this embodiment, the water tank stores water to be supplied to the first cleaning module 120.

Each of the first cleaning module 120 and the second cleaning module 130 is configured to perform a mopping operation on a floor. In this embodiment, the first cleaning module 120 is configured to perform a wet-type mopping operation (mopping while supplying water), and the water supply module supplies water to the first cleaning module 120. In this embodiment, the second cleaning module 130 is configured to perform a dry-type mopping operation (mopping without the supply of water), and the water supply module does not supply water to the second cleaning module 130. In this embodiment, the water supply module supplies water only to the first cleaning module 120, rather than to both the first cleaning module 120 and the second cleaning module 130. Since the robot cleaner 100 is implemented as in this embodiment, when the robot cleaner 100 moves forwards, the second cleaning module 130 is capable of performing a dry-type mopping operation on a floor surface that has been subjected to the wet-type mopping operation of the first cleaning module 120.

Hereinafter, the first cleaning module 120 will be described as performing a wet-type mopping operation, and the second cleaning module 130 will be described as performing a dry-type mopping operation. However, the present invention is not necessarily limited thereto. The water supply module may be configured to supply water to the second cleaning module 130 rather than to the first cleaning module 120, or to supply water to both the first cleaning module 120 and the second cleaning module 130.

The robot cleaner 100 includes a battery 160 for supplying power. The battery 160 may supply power required for the rotational motion of the first cleaning module 120.

The battery 160 may supply power required for the rotational motion of the second cleaning module 130.

The robot cleaner 100 includes a case 11 defining the appearance of the robot cleaner. The case 100 defines an upper surface, a front surface, a rear surface, a left side surface and a right side surface of the body 110. The robot cleaner 100 may include a base 13 defining the lower surface of the body 110. The first cleaning module 120 is fixed to the base 13. The second cleaning module 130 is also fixed to the base 13. The robot cleaner 100 includes a rolling mop housing 12, which is disposed on the base 130 and is depressed upwards so as to receive an upper portion of the rolling mop 130 a. The controller 20, the water supply module and the battery 160 are disposed in the internal space defined by the case 11, the base 13 and the rolling mop housing 12.

The robot cleaner 100 includes a water tank lid 153 for opening and closing the water tank. The water tank lid 153 is disposed on the upper surface of the body 110. The robot cleaner 100 may include a water-level indicator (not shown) configured to indicate the level of water in the water tank. The water-level indicator may be formed of a transparent material so as to allow the level of water in the water tank in the body 110 to be visible.

The robot cleaner 100 includes an obstacle sensor 16 for detecting an obstacle present in front of the robot cleaner 100. The robot cleaner 100 may include a plurality of obstacle sensors 16 a, 16 b and 16 c. The plurality of obstacle sensors 16 a, 16 b and 16 c are disposed on the front surface of the body 110.

The robot cleaner 100 includes a cliff sensor 17 for detecting a cliff present on a floor in a cleaning region. The robot cleaner 100 may include a plurality of cliff sensors 17 a, 17 b and 17 c). The cliff sensor 17 a may be configured to detect a cliff present in front of the first cleaning module 120. The cliff sensors 17 b and 17 c may be configured to detect a cliff present behind the second cleaning module 130.

The robot cleaner 100 may include a power switch (not shown) for turning on or off the supply of power. The robot cleaner 100 may include an input unit (not shown) for enabling various user instructions to be input. The robot cleaner 100 may include a communication module (not shown) for performing communication with an external device.

The robot cleaner 100 includes an ultraviolet LED 18 for radiating ultraviolet rays downwards. The ultraviolet LED 18 is disposed between the first cleaning module 120 and the second cleaning module 130. The ultraviolet LED 18 is disposed on the lower surface of the body 110 so as to radiate ultraviolet rays to the floor. The ultraviolet LED is disposed on the lower surface of the base 13. The robot cleaner 100 may include a plurality of ultraviolet LEDs 18 a and 18 b. The plurality of ultraviolet LEDs 18 a and 18 b include an ultraviolet LED 18 a disposed between the left spin mop 120 a and the rolling mop 130 a and an ultraviolet LED 18 b disposed between the right spin mop 120 b and the rolling mop 130 a. Accordingly, when the robot cleaner 100 moves forwards while performing cleaning, the ultraviolet LEDs radiate ultraviolet rays to the floor, which has been subjected to a mopping operation performed by the first cleaning module 120 so as to sterilize the floor, and then the second cleaning module 130 performs a cleaning operation on the floor, which has been sterilized by the ultraviolet rays.

The robot cleaner 100 includes the controller 20 for controlling autonomous travel.

The controller 20 may process signals detected by a sensor unit 810 (FIG. 8). For example, the controller 20 may process signals detected by the obstacle sensor 150 or the cliff sensor 17. The controller 20 may process signals of the input unit or signals input through the communication module. The controller 20 includes a PCB 20 disposed in the body 110.

The body 110 defines the appearance of the robot cleaner. The body 110 includes a first part (not shown) disposed above the first cleaning module 120, and a second part (not shown) disposed above the second cleaning module 130. The first part and the second part are integrally formed with each other. The body 110 is depressed upwards at the lower surface thereof between the first cleaning module 120 and the second cleaning module 130 so as to define a body gap (not shown). The body gap may be disposed between the first part and the second part. The body gap may be formed by depressing the left and right side surfaces of the body 110 inwards.

The body 110 includes a bumper 115 for detecting an external impact. The bumper 115 is disposed above the rotating plate 122 of the first cleaning module 120. The bumper 115 is disposed at a front side and a lateral side of the body 110. The bumper 115 includes a plurality of bumpers 115 a and 115 b. The bumper 115 a is disposed at a front side and the left side of the left spin mop 120 a. The bumper 115 b is disposed at a front side and a right side of the right spin mop 120 b.

The body 110 includes the case 11 and the base 13, which define the appearance of the robot cleaner.

The base 13 is provided with an opening in which the tilting frame 125 is disposed. The tilting frame 125 is connected to the base 13 via the tilting rotating shaft 126. The tilting rotating shaft 126 is rotatably secured to the base 13.

The base 13 includes a limiter for limiting the rotation range of the tilting frame 125. The limiter may include an upper-end limiter 13 d and a lower-end limiter (not shown).

The base 13 includes an upper-end limiter 13 d for limiting the upward-rotation range of the tilting frame 125. A left upper-end limiter 13 d may be disposed at the left side of the left tilting frame 125. A right upper-end limiter 13 d may be disposed at a right side of the right tilting frame 125. The left upper-end limiter 13 d is disposed so as to be capable of contacting an upper-end limiter contact portion 125 f of the left spin mop module 120. The right upper-end limiter 13 d is disposed to be capable of contacting an upper-end limiter contact portion 125 f of the right spin mop module 120. The upper-end limiter contact portion 125 f may be disposed at the tilting frame 125. When the robot cleaner 100 is normally disposed on an external horizontal surface, the upper-end limiter contact portion 125 f is in contact with the upper-end limiter 13 d, and inclined angles Ag1 and Ag2 have the minimum value.

The base 13 includes a lower-end limiter for limiting the downward rotation range of the tilting frame 125. The lower-end limiter may be disposed at the inner surface of the base 13. The lower-end limiter may be disposed below the spin drive unit 124. The lower-end limiter is configured to come into contact with a lower-end limiter contact portion (not shown) in the state in which the tilting frame 125 is maximally rotated downwards. The lower-end limiter contact portion may be disposed at the lower surface of the spin drive unit 124. When the robot cleaner is normally disposed on an external horizontal surface, the lower-end limiter contact portion is spaced apart from the lower-end limiter. When there is no force with which lower surfaces of the spin mops 120 a and 120 b are pushed upward, the tilting frame 125 is rotated to the maximum angle and the lower-end limiter contact portion comes into contact with the lower-end limiter with the result that the inclined angles Ag1 and Ag2 are increased to the maximum value.

The base 13 includes a second support 13 b for fixing an end of the elastic member 129. When the tilting frame 125 is rotated, the elastic member 129 is elastically deformed or restored by a first support 125 d fixed to the tilting frame 125 and the second support 13 b fixed to the base 13.

The base 13 includes a tilting rotating shaft support 13 c for supporting the tilting rotating shaft 126. The tilting rotating shaft support 13 c supports opposite ends of the tilting rotating shaft 126.

The base 13 may include a separate support member 13 a for supporting the tilting frame 125. The support member 13 a may be prepared as a separate component independent of the base 13. The support member 13 a extends along a peripheral area of the opening formed in the lower surface of the base 13. The support member 13 a may be provided at the center thereof with an opening in which the tilting rotating shaft 126 is disposed.

The support member 13 a may include the second support 13 b. The support member 13 a may include the tilting rotating shaft support 13 c. The support member 13 a may include the upper-end limiter 13 d. The support member 13 a includes a support-member-fixing portion 13 e coupled to the base 13.

Referring to FIGS. 2 to 4 and FIG. 5b , the second cleaning module 130 is disposed behind the first cleaning module 120 so as to come into contact with a floor. The second cleaning module 130 is configured to perform a mopping operation while in contact with a floor as the body 110 moves. The second cleaning module 130 is configured to perform a dry-type mopping operation.

The second cleaning module 130 may include the rolling mop 130 a, which rotates about the rotational axis Or, which extends horizontally. Although the rotational axis Or extends in a lateral direction in this embodiment, the rotational axis may extend in an anteroposterior direction or in a direction intermediate to the anteroposterior direction and the lateral direction in other embodiments. Accordingly, the rotational motion of the rolling mop 130 a may provide the body 110 with a moving force in a horizontal direction (in a direction perpendicular to the rotational axis Or). Since the moving force resulting from the rolling mop 130 a is additionally provided in addition to the moving force that is provided to the body 110 by the first cleaning module 120, it is possible for the robot cleaner 100 to variously travel.

In this embodiment, the second cleaning module 130 includes the rolling mop 130 a, which rotates about the rotational axis Or, which extends laterally. The rolling mop 130 a may rotate about the rotational axis Or extending in a direction parallel to an array direction of the left spin mop 120 a and the right spin mop 120 b. Accordingly, the body 110 may be provided with a moving force in an anteroposterior direction by virtue of the rotational motion. Since a moving force in an anteroposterior direction resulting from the rolling mop 130 a is additionally provided in addition to the moving force that is provided to the body 111 by virtue of the first cleaning module 120, it is possible for the robot cleaner 100 to travel more variously and efficiently.

Referring to FIG. 4, when viewed from a lateral side, a clockwise direction, among rotational directions of the rolling mop 130 a, is defined as a third forward direction w3 f, and a counterclockwise direction is defined as a third reverse direction.

When the robot cleaner 100 moves forwards, the rolling mop 130 a performs a mopping operation along a floor area, which has been cleaned by the first cleaning module 120. Since the rolling mop 130 a is configured to perform a dry-type mopping operation, the rolling mop 130 a is able to remove moisture from a floor area that has been subjected to a wet-type mopping operation of the left spin mop 120 a and the right spin mop 120 b. Although the second cleaning module 130 includes a single rolling mop 130 a in this embodiment, the second cleaning module 130 may include a plurality of rolling mops in other embodiments. In this case, the plurality of rolling mops may be rotated about a plurality of rotational axes parallel to each other.

The second cleaning module 130 includes a mop 131. A portion of the weight of the body 110 is transmitted to the floor via the mop 131. The mop 131 is disposed to surround a rotating member 132. The mop 131 is disposed along a circumference defined about the rotational axis Or. The mop 131 may be fixedly coupled to the rotating member 132, or may be detachably coupled to the rotating member 132.

The second cleaning module 130 includes the rotating member 132, which is rotatable. The rotating member 132 holds the mop 131 of the rolling mop 130 a. The rotating member 132 is able to integrally rotate the mop 131. The rotating member 132 is rotated by driving force transmitted from a rolling drive unit 137. The rotating member 132 is rotated about the rotational axis Or.

The rotating member 132 is configured to have a cylindrical form. The rotating member 132 extends in the direction of the rotational axis Or. The rotating member 132 defines a cavity 132 s therein. The mop 131 is fixed to the outer circumferential surface of the rotating member 132.

The second cleaning module 130 includes a first shaft portion 134 disposed at one end of the rotating member 132. The second cleaning module 130 includes a second shaft portion 135 disposed at the other end of the rotating member 132. The first shaft portion 134 and the second shaft portion 135 are disposed at opposite ends of the second cleaning module 130 in the direction of the rotational axis Or. In this embodiment, the first shaft portion 134 is disposed at the right end of the rotating member 132, and the second shaft portion 135 is disposed at the left end of the rotating member 132. One end of the rotating member 132 is depressed inwards, and the first shaft portion 134 is disposed in the depressed portion of the one end of the rotating member 132. The other end of the rotating member 132 is also depressed inwards, and the second shaft portion 135 is disposed in the depressed portion of the other end of the rotating member 132.

The first shaft portion 134 connects the one end of the rotating member 132 to the body 110. The first shaft portion 134 is fixedly connected to the rotating member 132. The first shaft portion 134 projects in the direction of the rotational axis Or. In this embodiment, the first shaft portion 134 projects rightward. The first shaft portion 134 is fitted into a hole formed in driving force transmitter 137 a and is thus integrally rotated with the driving force transmitter 137 a. The first shaft portion 134 is configured to have a shape other than a circular shape (for example, a polygonal shape) in a section perpendicular to the rotational axis Or, and the driving force transmitter 137 a is provided with the hole having a sectional shape corresponding to the section of the first shaft portion 134.

The second shaft portion 135 connects the other end of the rotating member 132 to the body 110. The second shaft portion 135 is rotatably connected to the rotating member 132. The second shaft portion 135 projects in the direction of the rotational axis Or. In this embodiment, the second shaft portion 135 projects leftward. The second shaft portion 135 is fixedly fitted into a hole formed in the body 110 and in a coupler 117. When the first shaft portion 134 is rotated by the driving force transmitter 137 a, the rotating member 132 and the mop 132 are integrally rotated with the first shaft portion 134, and the second shaft portion 135 is fixed and is rotated relative to the rotating member 132. A bearing may be provided between the second shaft portion 135 and the rotating member 132. The second shaft portion 135 is configured to have a shape (for example, a polygonal shape) other than a circular shape in a section perpendicular to the rotational axis Or, and the hole formed in the body 110 and/or the coupler 117 has a sectional shape corresponding to the section of the second shaft portion 135.

The second cleaning module 130 includes the rolling drive unit 137 for supplying the driving force required for rotation of the rolling mop 130 a. The rolling drive unit 137 provides driving force required for rotation of the rotating member 132. The rolling drive unit 137 includes a motor 137 d. The motor 137 d is disposed in the body 110. The rolling drive unit 137 includes a gear assembly 137 c for transmitting a rotational force. The gear assembly 137 c includes a plurality of gears, which are engaged with each other and are rotated. For example, the plurality of gears may include a drive gear, which is configured to be integrally rotated with the shaft of the motor 137 d, and a driven gear, which is engaged with the drive gear and is rotated. The driven gear may include a plurality of driven gears, which are engaged with each other and are rotated. The rolling drive unit 137 may include a shaft 137 b, which is integrally rotated with one of the plurality of driven gears. The rolling drive unit 137 may include the driving force transmitter 137 a for transmitting a rotational force to the first shaft portion 134. The shaft 137 b transmits the rotational force of the one of the plurality of driven gears to the driving force transmitter 137 a. The driving force transmitter 137 a includes a hole into which the first shaft portion 134 is fitted. The shaft 137 b, the driving force transmitter 137 a and the first shaft portion 134 are integrally rotated.

The robot cleaner 100 may include a coupler, which is detachably provided to the body 110. The coupler 117 is disposed at the base 13. The coupler 117 supports the lower end of the second shaft portion 135. The second shaft portion 135 is supported by the base 13. The coupler 117 may define a hole into which the second shaft portion 135 is fitted. By virtue of the coupler 117, the rotating member 132 and the mop 131 may be removed from or coupled to the body 110. For example, in the state in which the coupler 117 is removed, one of opposite ends of the rotating member 132, at which the second shaft portion 135 is disposed, may be pulled out of the body 110, and the first shaft portion 134 may then be easily removed from the driving force transmitter 137 a. In contrast, in the state in which the coupler 117 is removed, the end of the first shaft portion 134 may be fitted into the hole in the driving force transmitter 137 a, and the second shaft portion 135 and the coupler 117 may be fitted into the body. In order to maintain the state in which the rotating member 132 is coupled to the body 110, the coupler 117 may be fixed to the body 110 by a user. In order to separate the rotating member 132 from the body 110, the coupler 117 may be separated from the body 110 by a user.

Referring to FIGS. 1 to 7, the first cleaning module 120 includes the left spin mop 120 a and the right spin mop 120 b, which are rotated clockwise or counterclockwise while in contact with a floor, when viewed from above. The first cleaning module 120 is configured to perform a mopping operation by virtue of rotation of the left spin mop 120 a and the right spin mop 120 b.

Among components of the first cleaning module 120, a component that is denoted by a term to which “left” is prepended indicates a component for operating the left spin mop 120 a, and a component, which is denoted by a term to which “right” is prepended indicates a component for operating the right spin mop 120 b. When there is no discrimination between left and right in the description regarding components of the first cleaning module 120, the description may be applied to both left and right.

Referring to FIG. 4, the point, at which the rotational axis of the left spin mop 120 and the lower surface of the left spin mop 120 a intersect each other is defined as the rotational center Osa of the left spin mop 120 a, and the point, at which the rotational axis of the right spin mop 120 b and the lower surface of the right spin mop 120 b intersect each other is defined as the rotational center Osb of the right spin mop 120 b. When viewed from below, the clockwise direction of the left spin mop 120 a is defined as a first forward direction w1 f, and the counterclockwise direction of the left spin mop 120 a is defined as a first reverse direction w1 r. When viewed from below, the counterclockwise direction of the right spin mop 120 b is defined as a second forward direction w2 f, and the clockwise direction of the right spin mop 120 b is defined as a second reverse direction w2 r.

Referring to FIG. 4, when the left spin mop 120 a is rotated, the point Pla on the lower surface of the left spin mop 120 a to which the maximum frictional force is applied from a floor is positioned to the left side of the rotational center Osa of the left spin mop 120 a. It is possible to generate the maximum frictional force at the point Pla on the lower surface of the left spin mop 120 a by subjecting the point Pla to greater load than other points on the lower surface. Although the point Pla is positioned immediately to the left of the rotational center Osa in this embodiment, the point Pla may be positioned left and to the front or rear of the rotational center Osa in other embodiments.

Referring to FIG. 4, when the right spin mop 120 b is rotated, the point Plb on the lower surface of the right spin mop 120 b to which the maximum frictional force is applied from a floor is positioned to the right side of the rotational center Osb of the right spin mop 120 b. It is possible to generate the maximum frictional force at the point Plb on the lower surface of the right spin mop 120 b by subjecting the point Plb to greater load than other points on the lower surface. Although the point Plb is positioned to the exact right side of the rotational center Osb in this embodiment, the point Plb may be positioned to the front or rear of the right side of the rotational center Osb in other embodiments.

The point Pla and the point Plb are disposed at positions symmetrical to each other in a lateral direction.

In order to subject the point Pla on the lower surface of the left spin mop 120 a to be subjected to the maximum frictional force from a floor (or in order to subject the point Plb on the lower surface of the right spin mop 120 b to the maximum frictional force from a floor), this may be implemented by the following embodiments.

In the embodiment shown in FIG. 3, the lower surface of the left spin mop 120 a may be inclined downwards in a direction toward the point Pla from the rotational center Osa. In this case, the point Pla becomes the lowest point Pla on the lower surface of the left spin mop 120 a. In this case, the angle defined between a virtual horizontal surface H and the lower surface I1 of the left spin mop 120 a is defined as an inclined angle Ag1, and the angle defined between a virtual horizontal surface H and the lower surface 12 of the right spin mop 120 b is defined as an inclined angle Ag2. In other words, the angle defined between the lower surface I1 of the left spin mop 120 a and an external horizontal surface H is an inclined angle Ag1, and the angle defined between the lower surface 12 of the right spin mop 120 b and an external horizontal surface H is an inclined angle Ag2. The two inclined angles Ag1 and Ag2 may be the same as each other.

In another embodiment, the lower surface of the left spin mop 120 a may be disposed to be horizontal. It is possible to apply a moment to the left spin mop 120 a by means of an elastic member. The moment applied to the left spin mop 120 a is a clockwise moment when viewed from the front. In this case, even when the left spin mop 120 a is disposed parallel to an external horizontal surface H, the point Pla comes into contact with the external horizontal surface H with the maximum force, thereby generating the maximum frictional force. First and second embodiments for implementing this are as follows.

In the embodiment shown in FIG. 3, each of the lower surface of the left spin mop 120 a and the lower surface of the right spin mop 120 b is disposed to be inclined. Each of the inclined angle Ag1 of the left spin mop 120 a and the inclined angle Ag2 of the right spin mop 120 b defines an acute angle. In this embodiment, each of the inclined angles Ag1 and Ag2 ranges from about 30 degrees to about 6 degrees. Each of the inclined angles Ag1 and Ag2 may be set to be small to such an extent that the point to which the maximum frictional force is applied becomes the point Pla or Plb and the entire lower surface of the mop member 121 comes into contact with a floor by rotational motion of a corresponding one of left spin mop 120 a and the right spin mop 120 b.

The lower surface of the left spin mop 120 a is inclined downwards and to the left. The lower surface of the right spin mop 120 b is inclined downwards and to the right. Referring to FIG. 4, the left spin mop 120 a has the lowest point Pla at the left region of the lower surface thereof. The left spin mop 120 a has the highest point Pha at the right region of the lower surface thereof. The right spin mop 120 b has the lowest point Plb at the right region of the lower surface thereof. The right spin mop 120 b has the highest point Phb at the left region of the lower surface thereof.

Referring to FIG. 4, movement of the robot cleaner 100 is achieved using a frictional force generated between the first cleaning module 120 and/or the second cleaning module 130 and a floor.

The first cleaning module 120 may generate forward-movement frictional force for moving the body 110 forwards or rearward-movement frictional force for moving the body 110 backwards. The first cleaning module 120 may generate leftward-moment frictional force for rotating the body leftwards or rightward-moment frictional force for rotating the body 110 rightwards. The first cleaning module 120 may generate a combinational frictional force of one of the forward-movement frictional force and the rearward-movement frictional force and one of the leftward-moment frictional force and the rightward-moment frictional force.

The second cleaning module 130 may generate a forward-movement frictional force for moving the body 110 forwards or a rearward-movement frictional force for moving the body 110 rearwards.

In order for the first cleaning module 120 to generate the forward-movement frictional force, the left spin mop 120 a may be rotated in the first forward direction w1 f at a predetermined RPM while the right spin mop 120 b may be rotated in the second forward direction w2 f at the same RPM.

In order for the second cleaning module 130 to generate the forward-movement frictional force, the rolling mop 130 a may be rotated in the third forward direction w3 f.

In order for the first cleaning module 120 to generate the rearward-movement frictional force, the left spin mop 120 a may be rotated in the first reverse direction w1 r at a predetermined RPM while the right spin mop 120 b may be rotated in the second reverse direction w2 r at the same RPM.

In order for the second cleaning module 130 to generate the rearward-movement frictional force, the rolling mop 130 a may be rotated in the third reverse direction w3 r.

In order for the first cleaning module 120 to generate the rightward-moment frictional force, the left spin mop 120 a is rotated in the first forward direction w1 f at a predetermined RPM while the right spin mop 120 b may be rotated in the second reverse direction w2 r, may be stopped without rotational motion or may be rotated in the second forward direction w2 f at a RPM lower than the above RPM.

In order for the first cleaning module 120 to generate the leftward-moment frictional force, the right spin mop 120 b may be rotated in the second forward direction w2 f at a predetermined RPM while the left spin mop 120 a may be rotated in the first reverse direction w1 r, may be stopped without rotational motion or may be rotated in the first forward direction w1 f at a RPM lower than the above RPM.

By virtue of a combination of the frictional force generated by the first cleaning module 120 and the frictional force generated by the second cleaning module 130, the body 110 may be moved or stopped in place.

In order to move the robot cleaner 100 forward in a straight line, both the first cleaning module 120 and the second cleaning module 130 may generate the forward-movement frictional force. In another example, one of the first cleaning module 120 and the second cleaning module 130 generates the forward-movement frictional force while the other may be maintained in a stopped state without rotational motion. In a further example, one of the first cleaning module 120 and the second cleaning module 130 generates a relatively higher forward-movement frictional force while the other may generate a relatively lower rearward-movement frictional force.

In order to move the robot cleaner 100 backwards in a straight line, both the first cleaning module 120 and the second cleaning module 130 may generate the rearward-movement frictional force. In another example, one of the first cleaning module 120 and the second cleaning module 130 may generate the rearward-movement frictional force while the other may be maintained in a stopped state without rotational motion. In a further example, one of the first cleaning module 120 and the second cleaning module 130 generates a relatively higher rearward-movement frictional force while the other may generate a relatively lower forward-movement frictional force.

In order to turn the robot cleaner 100 to the right, the first cleaning module 120 may generate the rightward-moment frictional force while the rolling mop 130 a may be rotated in the third forward direction w3 f, may be stopped without rotational motion or may be rotated in the third reverse direction w3 r.

In order to turn the robot cleaner 100 to the left the first cleaning module 120 may generate the leftward-moment frictional force while the rolling mop 130 a may be rotated in the third forward direction w3 f, may be stopped without rotational motion or may be rotated in the third reverse direction w3 r.

In order to maintain the robot cleaner 100 in place, both the first cleaning module 120 and the second cleaning module 130 may be maintained in a stopped state without rotational motion. In another example, one of the first cleaning module 120 and the second cleaning module 130 may generate the forward-movement frictional force while the other may generate the rearward-movement frictional force having the same strength as that of the forward-movement frictional force. Particularly, in the latter case, both the first cleaning module 120 and the second cleaning module 130 may be rotated so as to perform a mopping operation on a predetermined area of a floor while the body 110 may be stopped in place.

According to the specific traveling control of the body 110, the rotational direction of the rolling mop 130 a may be changed. Accordingly, since it is possible to combine the frictional force generated by the first cleaning module 120 with one of the forward-movement frictional force and the rearward-movement frictional force generated by the rolling mop 130 a, a greater variety of motions of the robot cleaner 100 may be obtained. Specifically, the highest speed that the robot cleaner 100 can travel in the anteroposterior direction may be further increased, and the turning radius with which the robot cleaner 100 is turned leftward or rightward may be variously changed. In addition, the robot cleaner 100 may be turned leftward or rightward while moving rearward, and it is possible to perform a mopping operation by virtue of the rotational motion while the body 110 is stopped in place.

When the first cleaning module 120 performs a predetermined rotational motion (a motion generating the forward-movement frictional force, the rearward-movement frictional force, the leftward-moment frictional force or the rightward-moment frictional force), the rolling mop 130 a may perform two or more different rotational motions. When the first cleaning module performs a predetermined rotational motion, the rolling mop 130 a may be controlled to be rotated in the third forward direction w3 f. When the first cleaning module performs a predetermined rotational motion, the rolling mop 130 a may be controlled to be rotated in the third reverse direction w3 r. When the first cleaning module performs a predetermined rotational motion, the rolling mop 130 a may be controlled to be stopped without rotational motion. When the first cleaning module performs a predetermined rotational motion, the rolling mop 130 a may be controlled to be rotated in the third forward direction w3 f. When the first cleaning module performs a predetermined rotational motion, the rolling mop 130 a may be controlled to be rotated in the third forward direction w3 f at one of two or more predetermined RPMs. When the first cleaning module performs a predetermined rotational motion, the rolling mop 130 a may be controlled to be rotated in the third rearward direction w3 r at one of two or more predetermined RPMs. Accordingly, it is possible to realize various traveling orbits and traveling speeds of the robot cleaner 100.

The range of the floor with which the rolling mop 130 a comes into contact may be elongated laterally. The right end of the left spin mop 120 a and the left end of the right spin mop 120 b may be spaced apart from each other by a predetermined distance. When viewed from the front, the range of the floor with which the rolling mop 130 a comes into contact may overlap the entire gap between the left spin mop 120 a and the right spin mop 120 b. The gap between the left spin mop 120 a and the right spin mop 120 b is a range which is not sufficiently subjected to the mopping operation performed by the first cleaning module 120. When the robot cleaner 100 travels in an anteroposterior direction, the rolling mop 130 a performs a mopping operation on an area of a floor corresponding to the gap, thereby complementing the mopping operation performed by the first cleaning module 120.

An area of a floor with which the rolling mop 130 a comes into contact may be elongated laterally. When viewed from the front, a range of a floor with which the rolling mop 130 a comes into contact may overlap the entire range between the rotational center Osa of the left spin mop 120 a and the rotational center Osb of the right spin mop 120 b. The right portion of the left spin mop 120 a with respect to the rotational center Osa and the left portion of the right spin mop 120 b with respect to the rotational center Osb are subjected to relatively lower frictional force. Hence, the portions may not be subjected to sufficient mopping operation, compared to the left portion of the left spin mop 120 a with respect to the rotational center Osa and the right portion of the right spin mop 120 b with respect to the rotational center Osb. The rolling mop 130 a may serve to complement a mopping operation performed by the first cleaning module 120 by performing a mopping operation on a range between the rotational center Osa of the left spin mop 120 a and the rotational center Osb of the right spin mop 120 b while the robot cleaner 100 travels anteroposteriorly.

The first cleaning module 120 includes the mop members 121, which are coupled to lower sides of the rotating plates 122 so as to come into contact with a floor. The mop members 121 are respectively disposed on the lower surface of the left spin mop 120 a and the lower surface of the right spin mop 120 b. The mop members 121 may be fixedly disposed on the rotating plates 122, or may be detachably disposed on the rotating plates 122. The mop members 121 may be detachably coupled to the rotating plates 122 by means of Velcro fasteners, i.e. hook-loop fasteners. The mop member 121 may be composed of only a mop, or may be composed of a mop and a spacer (not shown). The mop comes into direct contact with a floor so as to perform a mopping operation. The spacer may be disposed between the rotating plate 122 and the mop so as to adjust the position of the mop. The spacer may be detachably coupled to the rotating plate 122, and the mop may be detachably coupled to the spacer. It goes without saying that the mop 121 may be directly detachably coupled to the rotating plate 122 without using the spacer.

Referring to FIG. 5a , the first cleaning module 120 includes a spin rotating shaft 128 for rotating the rotating plate 122. The spin rotating shaft 128 is fixed to the rotating plate 122 so as to transmit the rotational force of the spin drive unit 124 to the rotating plate 122. The spin rotating shaft 128 is connected to the upper side of the rotating plate 122. The spin rotating shaft 128 is disposed at the center of an upper portion of the rotating plate 122.

The spin rotating shaft 128 is fixed to the rotational center Osa or Osb of the rotating plate 122. The spin rotating shaft 128 includes a gear holder (not shown) for holding a gear 127 b. The gear holder is disposed at the upper end of the spin rotating shaft 128.

The first cleaning module 120 includes a left spin rotating shaft 128, which is fixed to the left rotating plate 122 so as to rotate the left rotating plate 122, and a right spin rotating shaft 128, which is fixed to the right rotating plate 122 so as rotate the right rotating plate 122.

The spin rotating shaft 128 extends perpendicular to the rotating plate 122. The left spin rotating shaft 128 is disposed to be perpendicular to the lower surface of the left spin mop 120 a, and the right spin rotating shaft 128 is disposed to be perpendicular to the lower surface of the right spin mop 120 b. In an embodiment in which the lower surface of each of the spin mops 120 a and 120 b is inclined with respect to a horizontal surface, the spin rotating shaft 128 is inclined with respect to a vertical axis. The spin rotating shaft 128 is oriented such that the upper end thereof is inclined in one direction with respect to the lower end thereof. The left spin rotating shaft 128 is oriented such that the upper end thereof is inclined leftward with respect to the lower end thereof. The right spin rotating shaft 128 is oriented such that the upper end thereof is inclined rightward with respect to the lower end thereof.

The inclined angle of the spin rotating shaft 128 with respect to a vertical axis may be changed according to the rotation of the tilting frame 125 about the tilting rotating shaft 126. The spin rotating shaft 128 is rotatably coupled to the tilting frame 125 so as to be integrally inclined together with the tilting frame 125. When the tilting frame 125 is inclined, the spin drive unit 124, the drive transmission unit 127, the spin rotating shaft 128, the rotating plate 122, the water supply receiver and the mop member 121 are integrally inclined together with the tilting frame 125.

The first cleaning module 120 includes the water supply receiver, which is disposed at the upper side of the rotating plate 122 so as to receive water therein.

The first cleaning module 120 includes a spin drive unit 124 for supplying the driving force required for rotation of the spin mops 120 a and 120 b. The spin drive unit 124 may be an assembly including at least a motor. The first cleaning module 120 includes a left spin drive unit 124 for supplying the driving force required for rotation of the left spin rotating shaft 128, and a right spin drive unit 124 for supplying the driving force required for rotation of the right spin rotating shaft 128. The left spin drive unit 124 supplies the driving force required for rotation of the left spin rotating shaft 128. The right spin drive unit 124 supplies the driving force required for rotation of the right spin rotating shaft 128.

The first cleaning module 120 includes the drive transmission unit 127 for transmitting the rotational force of the spin drive unit 124 to the spin rotating shaft 128. The drive transmission unit 127 may include a plurality of gears and/or belts and the like.

In this embodiment, the drive transmission unit 127 includes a first gear 127 a fixed to the rotating shaft of the motor 124. The first gear 127 a may be a worm gear. The drive transmission unit 127 may include a second gear 127 b, which is engaged with the first gear 127 a and rotated. The second gear 127 b may be a spur gear. The second gear 127 b is fixed to the spin rotating shaft 128 so as to rotate the spin rotating shaft 128 when the second gear 127 b is rotated.

The first cleaning module 120 includes the tilting frame 125, which is inclined within a predetermined angular range. The tilting frame 125 enables the inclined angles Ag1 and Ag2 to be changed according to the state of the floor. The tilting frame 125 may serve as a suspension for the spin mops 120 a and 120 b (functions of supporting a weight and of mitigating vertical vibration). The tilting frame 125 is supported so as to be capable of being inclined with respect to the base 13. The tilting frame 125 rotatably supports the spin rotating shaft 128.

The first cleaning module 120 includes the left tilting frame 125 for supporting the left spin rotating shaft 128. The left tilting frame 125 is rotatable within a predetermined range about the left tilting rotating shaft 126.

The first cleaning module 120 includes the right tilting frame 125 for supporting the right spin rotating shaft 128. The right tilting frame 125 is rotatable within a predetermined range about the right tilting rotating shaft 126.

For example, when the left spin mop 120 a comes into contact with a depressed portion of an external floor, the inclined angle Ag1 of the left spin mop 120 a may be increased within a predetermined range by means of the left tilting frame 125. In this way, when the right spin mop 120 b comes into contact with a depressed portion of an external floor, the inclined angle Ag2 of the right spin mop 120 b may be increased within a predetermined range by means of the right tilting frame 125.

The tilting frame 125 includes a frame base 125 a defining the lower surface thereof. The spin rotating shaft 128 extends vertically through the frame base 125 a. The frame base 125 a may be formed to have a plate shape having a predetermined thickness in a vertical direction. The tilting rotating shaft 126 rotatably connects the frame base 125 a to the base 13.

The tilting frame 125 includes a water supply cabinet 125 b receiving the spin rotating shaft 128 therein. The water supply cabinet 125 b defines a space, which is depressed upwards from a lower side of the body 110 so as to receive an upper end of the water supply receiver. The water supply cabinet 125 b is fixed to the frame base 125 a. The water supply cabinet 125 b defines a space, which is depressed upwards from the lower surface of the frame base 125 a such that water is introduced into the space defined by the water supply cabinet 125 b through a water supply unit 125 c. The water supply cabinet 125 b may guide all of the water into the water supply receiver while minimizing splashing of water.

The water supply cabinet 125 b includes a rotating shaft support (not shown) for rotatably supporting the spin rotating shaft 128. A bearing B may be provided between the rotating shaft support and the spin rotating shaft 128. The bearing B may include a first bearing B1 disposed at a lower side and a second bearing B2 disposed at an upper side.

The lower end of the rotating shaft support is disposed in the water supply space defined in the water supply receiver. The inner circumferential surface of the rotating shaft supports the spin rotating shaft 128. The outer circumferential surface of the rotating shaft support faces the inner circumferential surface of the water supply receiver. Accordingly, it is possible to easily guide water into the water supply space while stably supporting the spin rotating shaft 128.

The lower end of the rotating shaft support is disposed between the spin rotating shaft 128 and the inner circumferential surface of the water supply receiver. The outer circumferential surface of the lower end of the rotating shaft support and the inner circumferential surface of the water supply receiver 123 are spaced apart from each other so as to define a water supply space Sw. An inclined portion is disposed at the lower end of the rotating shaft support.

The water supply cabinet 125 b includes a partition wall (not shown) projecting from the rotating shaft support. The partition wall covers the upper end of the water supply receiver 123. The partition wall covers the upper end and the outer circumferential surface of the water supply receiver 123. The partition wall is disposed in the centrifugal direction of the rotating shaft support. The partition wall is fixed to and supported by the frame base 125 a. The partition wall supports the rotating shaft support.

The tilting frame 125 includes the water supply unit 125 c for receiving water from the water supply module. The water supply unit 125 c receives water from a supply pipe 156. The water supply unit 125 c defines a water channel. The water supply unit 125 c guides water into the water supply receiver through the water supply cabinet 125 b. One end of the water channel defined by the water supply unit 125 c is connected to the end of the supply pipe 156. The other end of the water channel defined by the water supply unit 125 c is disposed in the water supply space Sw. The one end of the water channel defined by the water supply unit 125 c is disposed outside of the water supply cabinet 125 b and the other end of the water channel is disposed in the water supply cabinet 125 b (at which the water supply space is positioned). The water supply unit 125 c is fixedly disposed at the tilting frame 125. The water supply unit 125 c is fixed to the water supply cabinet 125 b.

The tilting frame 125 includes the first support 125 d for supporting one end of the elastic member 129. The other end of the elastic member 129 is supported by a second support 13 b disposed at the base 13. The second support 13 b may be formed at the support member 13 a of the base 13. As the tilting frame 125 is inclined about the tilting rotating shaft 126, the position of the first support 125 d varies and the length of the elastic member 129 varies.

The first support 125 d is fixed to the tilting frame 125. The first support 125 d is disposed at the right portion of the left tilting frame 125. The first support 125 d is also disposed at the left portion of the right tilting frame 125.

The second support 13 b is fixed to the base. The second support f13 b is disposed at the right region of the left first cleaning module 120. The second support 13 b is also disposed at the left region of the right first cleaning module 120.

The first support 125 d is fixed to the tilting frame 125. When the tilting frame 125 is inclined, the first support 125 d is inclined together with the tilting frame 125. The first support 125 d projects away from the tilting rotating shaft 126 such that a portion of the first support 125 d, to which the one end of the elastic member 129 is fixed, is positioned at a predetermined distance from the tilting rotating shaft 126. When the inclined angles Ag1 and Ag2 are decreased to the minimum, the first support 125 d is positioned closest to the second support 13 b. As the inclined angles Ag1 and Ag2 are decreased to the minimum, the elastic member 129 is elastically deformed to a tensioned state.

Referring to FIG. 5a , when viewed from the rear, when the left tilting frame 125 is rotated counterclockwise about the tilting rotating shaft 126, the second support 13 b is moved leftward, and the elastic member 129 is elastically restored while being shortened. When viewed from the rear, when the left tilting frame 125 is rotated clockwise about the tilting rotating shaft 126, the second support 13 b is moved rightward, and the elastic member 129 is elastically deformed while being elongated. When viewed from the rear, when the right tilting frame 125 is rotated clockwise about the tilting rotating shaft 126, the second support 13 b is moved rightward, and the elastic member 129 is elastically restored while being shortened. When viewed from the rear, when the right tilting frame 125 is rotated counterclockwise about the tilting rotating shaft 126, the second support 13 b is moved leftward, and the elastic member 129 is elastically deformed while being elongated.

The tilting frame 125 includes a motor support 125 e for supporting the spin drive unit 124. The motor support 125 e may support the drive transmission unit 127.

The tilting frame 125 includes the upper-end limiter contact portion 125 f, which is capable of coming into contact with the upper-end limiter 13 d. The upper surface of the upper-end limiter contact portion 125 f may come into contact with the lower surface of the upper-end limiter 13 d.

The left upper-end limiter contact portion 125 f may be disposed at the left end of the left tilting frame 125. The right upper-end limiter contact portion 125 f may be disposed at the right end of the right tilting frame 125.

The first cleaning module 120 includes the tilting rotating shaft 126, serving as the rotating shaft of the tilting frame 125. The tilting rotating shaft 126 extends in a direction perpendicular to the inclined direction of the spin mops 120 a or 120 b. The tilting rotating shaft 126 may extend horizontally. In this embodiment, the tilting rotating shaft 126 extends anteroposteriorly.

The first cleaning module 120 includes the left tilting rotating shaft 126, which extends in a direction perpendicular to the inclined direction of the lower surface of the left spin mop 120 a. The first cleaning module 120 includes the right tilting rotating shaft 126, which extends in a direction perpendicular to the inclined direction of the lower surface of the right spin mop 120 b.

The first cleaning module 120 includes the elastic member 129 for applying elastic force to the tilting frame 125. The elastic member 129 is elongated when the tilting frame 125 is rotated downwards, and is shortened when the tilting frame 125 is rotated upward. The elastic member 129 enables the tilting frame 125 to be operated in a shock-absorbing manner (in an elastic manner). The elastic member 129 applies a moment to the tilting frame 125 in the direction in which the inclined angles Ag1 and Ag2 are increased. The elastic member 129 may be disposed to extend laterally overall.

Referring to FIG. 6, the body 110 includes a battery support 14 for supporting the battery 160. The battery support 14 positions the battery 160 above the supply pipe. The battery support 14 functions to guide the position of the supply pipe 156.

FIG. 8 is a block diagram illustrating the control relationship among substantial components of the robot cleaner according to an embodiment of the present invention.

FIGS. 9 to 19 are views illustrating a method of controlling various traveling operations of the robot cleaner according to an embodiment of the present invention.

Referring to FIGS. 1 to 7, 8 and 9, the robot cleaner 100 according to an embodiment of the present invention may include the first cleaning module 120 including the left spin mop 120 a and the right spin mop 120 b, which are rotated clockwise or counterclockwise when viewed from above while in contact with the floor, the second cleaning module 130 disposed behind the first cleaning module 120, the second cleaning module 130 including the rolling mop 130 a, which is rotated clockwise or counterclockwise when viewed from the left while in contact with the floor, and which is spaced apart from the left and right spin mops 120 a and 120 b in an anteroposterior direction, and a controller 20 for controlling the rotational motion of the left spin mop 120 a and the right spin mop 120 b and the rotational motion of the rolling mop 130 a.

The robot cleaner 100 according to an embodiment of the present invention may travel by virtue of a front wheel composed of a pair of spin mops 120 a and 120 b and a rear wheel composed of the rolling mop 130 a.

The spin mops 120 a and 120 b may generate driving force required for traveling in a desired direction while performing a wet-type cleaning operation by supplying water.

The rolling mop 130 a may be rotated about the rotational axis extending horizontally. Specifically, when viewed from the left, the rolling mop 130 a may be rotated clockwise or counterclockwise.

The rolling mop 130 a, which is a rotatable cylindrical wet mop, may include a single rotating member 132 or a plurality thereof having a roller or cylinder shape, and the mop member 131 disposed to surround the rotating member 132 and composed of a fabric material having a high moisture content ratio and a high sweeping ability.

In forward traveling, the rolling mop 130 a may perform a mopping operation using the mop member 131 while moving along an area of a floor that has been subjected to a wet-type cleaning operation performed by the spin mops 120 a and 120 b.

The controller 20 may control the rotational motion of the left spin mop 120 a and the right spin mop 120 b and the rotational motion of the rolling mop 130 a. Furthermore, the controller 20 may independently control the two spin mops 120 a and 120 b and the single rear rolling mop 130 a.

In addition, the controller 20 may perform control so as to change the rotational direction and speed of the rolling mop 130 a, thereby controlling the acceleration or deceleration of the robot cleaner 100.

According to an embodiment of the present invention, it is possible to improve floor-cleaning performance, such as absorption of remaining moisture and decontamination by means of the rear rolling mop 130 a, and it is possible to assist the body in traveling by control of the rotational direction and/or speed of the rear rolling mop 130 a.

Furthermore, according to an embodiment of the present invention, there are advantages of realizing various traveling motions as well as a rotary frictional cleaning operation by control of the rotational direction and speed of the front spin mops 120 a and 120 b and the rear rolling mop 130 a.

The controller 20 may control the traveling motion of the robot cleaner 100 by causing movement due to concurrent slipping of the spin mops 120 a and 120 b and the rolling mop 130 a, which correspond to front and rear wheels, and to the difference in drag force attributable to the difference in rotational speed and frictional force between the spin mops 120 a and 120 b and the rolling mop 130 a.

Furthermore, the rolling mop 130 a may be rotated in the same direction as the traveling direction due to rotation of the spin mops 120 a and 120 b so as to increase a ratio of the driving force of the rolling mop, thereby realizing high-speed traveling.

In addition, the rolling mop 130 a may be rotated in a direction opposite a traveling direction due to rotation of the spin mops 120 a and 120 b so as to make it possible to perform a backward traveling.

The rolling mop 130 a may be rotated in a direction opposite a traveling direction due to rotation of the spin mops 120 a and 120 b so as to maintain a equilibrium of rotational force between the rolling mop 130 a and the spin mops 120 a and 120 b, thereby causing the robot cleaner 100 to stand in place and thus enabling concentrated cleaning at a specific location.

Specifically, the controller 20 may control rotation of the spin mops 120 a and 120 b and the rolling mop 130 a so as to cause a traveling direction due to rotation of the spin mops 120 a and 120 b to be opposite a traveling direction due to rotation of the rolling mop 130 a. As a result, equilibrium in traveling force between forward travel and backward travel is established, thereby causing the robot cleaner 100 to stand in place.

In this case, since the spin mops 120 a and 120 b and the rolling mop 130 a continue to be rotated, it is possible to continuously perform a cleaning operation without cease.

The first cleaning module 120 may include the motor 124 for rotating the spin mops 120 a and 120 b. The motor 124 may include a left motor for rotating the left spin mop 120 a and a right motor for rotating the right spin mop 120 b.

The controller 20 may include a first motor drive unit 821 for driving the motor 124 for rotating the spin mops 120 a and 120 b.

By virtue of the control operation of a main controller 820 of the controller 20, the first motor drive unit 821 is controlled, and the motor 124 is driven by the first motor drive unit 821. Accordingly, the spin mops 120 a and 120 b are rotated by the motor 124.

The first motor drive unit 821, which is intended to drive the motor 124, may include an inverter (not shown), an inverter controller (not shown), a current detector (not shown) for detecting current flowing to the motor 124 and a voltage detector (not shown) for detecting the voltage applied to the motor 230. The first motor drive unit 821 may further include a converter for supplying direct-current input to the inverter (not shown).

The second cleaning module 130 may include the motor 137 d for rotating the rolling mop 130 a, and the controller 20 may include a second motor drive unit 822 for driving the motor 137 d.

By virtue of a control operation of the main controller 820 of the controller 20, the second motor drive unit 822 is controlled, and the motor 137 d is driven by the second motor drive unit 822. Accordingly, the rolling mop 130 a is rotated by the motor 137 d.

The second motor drive unit 822, which is intended to drive the motor 137 d, may include an inverter (not shown), an inverter controller (not shown), a current detector (not shown) for detecting the current flowing to the motor 137 d and a voltage detector (not shown) for detecting the voltage applied to the motor 137 d. The second motor drive unit 822 may further include a converter for supplying direct-current input to the inverter (not shown).

Although FIG. 8 illustrates an example in which the first and second motor drive units 821 and 822 are included in the controller 20, the present invention is not limited thereto.

For example, the first and second motor drive units 821 and 822 may be separately provided outside the controller 20 and may be operated under the control of the controller 20.

In addition, the first and second motor drive units 821 and 822 may be changed in the detailed configuration thereof depending on the type and specification of the motors 124 and 137 d.

The robot cleaner 100 according to an embodiment of the present invention may include a storage unit 830 for storing various data.

The storage unit 830, which is intended to store various information required for control of the robot cleaner 100, may include a volatile or non-volatile recording medium. The recording medium, which stores data readable by a microprocessor, may include a hard disk drive (HDD), a solid-state disk (SSD), a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disc, optical data storage, and the like.

In some embodiments, the storage unit 830 may store cleaning history information. The cleaning history information may be created every time a cleaning operation is performed.

The robot cleaner 100 may include a sensor unit 810 including a plurality of sensors for sensing various data associated with the operation and state of the robot cleaner 100.

The sensor unit 810 may include an obstacle sensor 811 for detecting an obstacle in front of the robot cleaner 100. The obstacle sensor 811 may include the plurality of sensors 16 a, 16 b and 16 c illustrated in FIG. 1.

The obstacle sensor 811 may include an infrared sensor, an ultrasonic sensor, an RF sensor, a geomagnetic sensor, a position-sensitive device (DSD) sensor and the like.

The position and type of the sensors included in the obstacle sensor 811 may be changed depending on the model of the robot cleaner, and the obstacle sensor 811 may further include various sensors.

The controller 20 may perform control so as to travel while skirting around a detected obstacle.

According to the present invention, the controller 20 may control various traveling motions by combining the motion of the spin mops 120 a and 120 b with the motion of the rolling mop 130 a.

Accordingly, the controller 20 may perform control so as to perform various skirting traveling operations according to an obstacle detected by the obstacle sensor 811.

The controller 20 may perform control so as to perform another skirting traveling operation according to on an obstacle detected by the obstacle sensor 811.

In addition, the sensor unit 810 may include a position sensor 812 for detecting the position of the robot cleaner 100 by receiving an external recognition signal.

For example, the position sensor 812 may be a UWB sensor employing an ultra-wideband (UWB) communication signal. Ultra-wideband communication, which is a technology for transmitting a signal through an ultra-wideband frequency with low power at short range, is advantageously used in an indoor space, in which an obstacle such as a wall is present, because it is excellent in distance resolution and penetrating power.

The controller 20 may detect the position of the robot cleaner 100 based on the signal received from the position sensor 812.

The external recognition signal is a signal transmitted from a signal generator such as a beacon located outside, and the signal generator may include a plurality of signal generators, which are provided at a plurality of separate sites.

Accordingly, the position sensor 812 is able to receive recognition signals transmitted from signal generators located at different sites.

The position sensor 812 may detect the position or traveling direction of the robot cleaner 100 by performing a comparison operation on information such as the strength and direction of the recognition signals received from the signal generators and the times at which the signals are received from the signal generators, information received at a previous site and information received at the current site.

The present invention may detect a spatial position from a relative distance with respect to three or more signal generators such as anchors or beacons, which generate specific recognition signals such as a UWB communication signal and a BLE signal.

In this case, the controller 20 may calculate speed information by performing a comparison operation between previous and current position information and receipt times of the previous and current position information based on the signal received at the position sensor 812. Thereafter, the controller 20 may control the rotation of the motor by estimating a target trajectory from calculation of a remaining distance and positional error with respect to the target trajectory and the current site based on the position information.

The sensor unit 810 may include an inertial measurement unit (IMU) 813. The inertial measurement unit 813 may include a gyro sensor 813 a, a geomagnetic sensor 813 b and an acceleration sensor 813 c. Alternatively, the sensor unit 810 may include the gyro sensor 813 a, the geomagnetic sensor 813 b and the acceleration sensor 813 c, which are independently provided.

The gyro sensor 813 a may detect a designated reference direction, the geomagnetic sensor 813 b may measure a heading angle (azimuthal angle), and the acceleration sensor 813 c may measure speed variation. Consequently, the inertial measurement unit sensor 813 may measure a moving speed, a direction, a gravitational force and an acceleration of the robot cleaner 100.

Each of the gyro sensor 813 a and the acceleration sensor 813 c may be a triaxial sensor. The information collected from the gyro sensor 813 a may be roll, pitch and yaw information, and the information collected from the acceleration sensor 813 c may be x-axis acceleration, y-axis acceleration and z-axis acceleration information.

The inertial measurement unit sensor 813 is able to measure accelerations in the traveling direction, lateral direction and height direction and an angular speed in rolling, pitching and yaw. The controller 20 is able to perform calculation of a speed and a heading angle of the robot cleaner 100 by integrating an acceleration and an angular speed obtained by the inertial measurement unit sensor 813.

The rolling mop 130 a or the like of the robot cleaner 100 according to an embodiment of the present invention may be configured such that the ratio between rolling motion and slipping motion is continuously changed according to the changing state of frictional force.

The robot cleaner 100 according to an embodiment of the present invention may have a compensation control structure for controlling movement, which is able to change the RPM of the motor by controlling the output of the plurality of motor drive units 821 and 822 according to variation of acceleration and angular speed obtained by the inertial measurement unit sensor 813.

For example, the controller 20 may control rotational speed of the left spin mop 120 a, the right spin mop 120 b and the rolling mop 130 a based on variation of acceleration and angular speed detected by the inertial measurement unit sensor 813.

The controller 20 is able to control the motors 124 and 137 d in such a manner as to respectively compensate output of the motors 124 and 137 d using information, such as acceleration and speed, detected by the sensor unit 810.

Furthermore, the controller 20 is able to detect current traveling conditions of the robot cleaner 100 based on predetermined information such as a heading angle information of the robot cleaner 100 detected by the sensor unit 810.

The sensor unit 810 may further include cliff sensors 814 for detecting a cliff present in a traveling area on a floor. Each of the cliff sensors 814 may be the cliff sensor 17 illustrated in FIG. 1.

The sensor unit 810 according to an embodiment of the present invention may further include a motor sensor 815 for detecting information about the operation and state of the motor. The motor sensor 815 may detect the value of the load current of the motor and the like.

In some embodiment, the motor sensor 815 may be simply composed of a current detector included in each of the first and second motor drive units 821 and 822.

The robot cleaner 100 according to the embodiment of the present invention includes the front spin mops 120 a and 120 b and the rear rolling mop 130 a. The front spin mops 120 a and 120 b and the rear rolling mop 130 a have a cooperative relationship with each other in a traveling operation.

The controller 20 may control the traveling operation of the robot cleaner 100 by controlling the rotational motion of the front spin mops 120 a and 120 b and the rear rolling mop 130 a.

The rotational direction of the left spin mop 120 a and the rotational direction of the right spin mop 120 b are opposite each other during a forwards or backwards traveling operation.

Specifically, the front spin mops 120 a and 120 b are rotated outwards when viewed from the front during a forward traveling operation, and are rotated inwards during a backward traveling operation.

During a left-turning operation, the rotational directions of the front spin mops 120 a and 120 b are the same.

For example, when the robot cleaner 100 intends to turn right, both the front spin mops 120 a and 120 b are rotated counterclockwise (when viewed from above). At this time, the right spin mop 120 b serves as the center point of the right-turning motion, and the opposite left spin mop 120 a serves to provide supplementary force for the right-turning motion.

In contrast, when the robot cleaner 100 tries to turn right, both the front spin mops 120 a and 120 b are rotated clockwise (when viewed from above). At this time, the left spin mop 120 a serves as the center point of the left-turning motion, and the opposite right spin mop 120 b serves to provided supplementary force for the left-turning motion.

In a forward traveling operation, the rear rolling mop 130 a is rotated forwards or serves to increase RPM.

In contrast, in a backward traveling operation, the rear rolling mop 130 a is rotated backwards or serves to decrease RPM.

Hereinafter, various motions of the rear spin mops 120 a and 120 b and the rear rolling mop 130 a during a traveling operation of the robot cleaner 100 will be described with reference to FIGS. 10 to 17.

Referring to FIG. 10, the controller 20 may control the robot cleaner 100 so as to perform a high-speed forward traveling operation by rotating the left spin mop 120 a and the right spin mop 120 b outwards while rotating the rolling mop 130 a forward.

Referring to FIG. 10(a), in a high-speed forward traveling operation, when viewed from above, the left spin mop 120 a is rotated counterclockwise and the right spin mop 120 b is rotated clockwise, that is, the front spin mops 120 a and 120 b are rotated outwards so as to enable the robot cleaner 100 to perform a forward traveling operation.

In this case, the rolling mop 130 a may be rotated forwards so as to provide supplementary force in a forward direction. Consequently, it is possible to increase acceleration in a forward direction.

Referring to FIG. 10(b), in a high-speed forward traveling operation, when viewed from below, the left spin mop 120 a is rotated clockwise and the right spin mop 120 b is rotated counterclockwise; that is, the rear spin mops 120 a and 120 b are rotated outwards so as to enable the robot cleaner 100 to perform a forward traveling operation.

In this case, the rolling mop 130 a may be rotated forwards so as to provide supplementary force in a forward direction. Consequently, it is possible to increase acceleration in a forward direction.

Thus, when both of the two front spin mops 120 a and 120 b and the rear rolling mop 130 a are rotated, the robot cleaner 100 is able to travel forward at a higher speed than when only the two spin mops 120 a and 120 b are rotated.

Accordingly, in a high-speed forward traveling operation, control is performed so as to cause the left spin mop 120 a and the right spin mop 120 b to be rotated outwards and to cause the rolling mop 130 a to be rotated forwards.

The controller 20 may perform control so as to perform various motions by controlling the rotational direction and speed of the rolling mop 130 a while the left spin mop 120 a and the right spin mop 120 b are rotated outward.

For example, the controller 20 may control the robot cleaner 100 to perform a stationary operation by causing the left spin mop 120 a and the right spin mop 120 b to be rotated outwards while causing the rolling mop 130 a to be rotated backwards at a first speed. Here, the first speed may be set so as to obtain a backward propulsive force equal to a forward propulsive force resulting from rotation of the left spin mop 120 a and the right spin mop 120 b.

Alternatively, the controller 20 may control the robot cleaner 100 so as to perform a low-speed forward traveling operation by causing the left spin mop 120 a and the right spin mop 120 b to be rotated outward while causing the rolling mop 130 a to be rotated backwards at a second speed. Here, the absolute value of the second speed may be lower than the absolute value of the first speed. Consequently, although the forward propulsive force becomes higher than the backward propulsive force, thereby enabling forward traveling operation, the speed of the robot cleaner 100 is decreased owing to the presence of the backward propulsive force.

Alternatively, the controller 20 may control the robot cleaner 100 so as to perform a low-speed backward traveling operation by causing the left spin mop 120 a and the right spin mop 120 b to be rotated outwards while causing the rolling mop 130 a to be rotated backwards at a higher speed than the first speed.

Referring to FIG. 11(a), when viewed from above, the left spin mop 120 a is rotated counterclockwise and the right spin mop 120 b is rotated clockwise; that is, the front spin mops 120 a and 120 b are rotated outwards so as to enable the robot cleaner 100 to perform a forward traveling operation.

In this case, the rolling mop 130 a may be rotated backwards so as to provide supplementary force in a backward direction opposite the forward direction. Consequently, it is possible to decrease acceleration in a forward direction.

Referring to FIG. 11(b), when viewed from below, the left spin mop 120 a is rotated clockwise and the right spin mop 120 b is rotated counterclockwise; that is, the rear spin mops 120 a and 120 b are rotated outwards so as to enable the robot cleaner 100 to perform a forward traveling operation.

In this case, the rolling mop 130 a may be rotated backwards so as to provide supplementary force in a backward direction. Consequently, it is possible to decrease acceleration in a forward direction.

Thus, when both of the two front spin mops 120 a and 120 b and the rear rolling mop 130 a are rotated, the robot cleaner 100 is able to travel forward at a lower speed than when only the two spin mops 120 a and 120 b are rotated. In other words, in order to increase cleaning performance, the robot cleaner 100 is able to travel forward at a lower speed while maintaining the rotational speed of the spin mops 120 a and 120 b.

Furthermore, when the rotational speed (RPM) of the rolling mop 130 a is further increased while the mops are rotated in the above respective rotational directions, the robot cleaner 100 is able to perform a mopping operation by rotating the spin mops 120 a and 120 b and the rolling mop 130 a while standing in place (stationary operation).

In addition, when the rotational speed (RPM) of the rolling mop 130 a is further increased while the mops are rotated in the above respective rotational directions, the robot cleaner 100 is able to perform a mopping operation by rotating the spin mops 120 a and 120 b and the rolling mop 130 a while performing a backward traveling operation.

Specifically, it is possible not only to increase cleaning performance by increasing the rotational speeds of the spin mops 120 a and 120 b and the rolling mop 130 a but also to perform a concentrated cleaning operation of intensively performing a mopping operation on a certain area by decreasing a moving speed of the robot cleaner 100 or maintaining the robot cleaner 100 in the stationary state.

Referring to FIG. 12, the controller 20 may control the robot cleaner 100 so as to perform a high-speed backward traveling operation by rotating the left spin mop 120 a and the right spin mop 120 b inward while rotating the rolling mop 130 a backwards.

Referring to FIG. 12(a), in a high-speed backward traveling operation, when viewed from above, the left spin mop 120 a is rotated clockwise and the right spin mop 120 b is rotated counterclockwise; that is, the front spin mops 120 a and 120 b are rotated inwards so as to enable the robot cleaner 100 to perform a backward traveling operation.

In this case, the rolling mop 130 a may be rotated backwards so as to provide supplementary force in a backward direction. Consequently, it is possible to increase acceleration in a backward direction.

Referring to FIG. 12(b), in a high-speed backward travelling operation, when viewed from below, the left spin mop 120 a is rotated counterclockwise and the right spin mop 120 b is rotated clockwise; that is, the rear spin mops 120 a and 120 b are rotated inwards so as to enable the robot cleaner 100 to perform a backward traveling operation.

In this case, the rolling mop 130 a may be rotated backwards so as to provide supplementary force in a backward direction. Consequently, it is possible to increase acceleration in a backward direction.

Thus, when both of the two front spin mops 120 a and 120 b and the rear rolling mop 130 a are rotated, the robot cleaner 100 is able to travel backwards at a higher speed than when only the two spin mops 120 a and 120 b are rotated.

Accordingly, in a high-speed backward traveling operation, control is performed so as to cause the left spin mop 120 a and the right spin mop 120 b to be rotated inwards and to cause the rolling mop 130 a to be rotated backwards.

The controller 20 may perform control so as to perform various motions by controlling the rotational direction and speed of the rolling mop 130 a while the left spin mot 120 a and the right spin mop 120 b are rotated inwards.

For example, the controller 20 may perform control the robot cleaner 100 to perform a stationary operation by causing the left spin mop 120 a and the right spin mop 120 b to be rotated inwards while causing the rolling mop 130 a to be rotated forwards at a third speed. Here, the third speed may be set so as to obtain a forward propulsive force equal to the backward propulsive force resulting from rotation of the left spin mop 120 a and the right spin mop 120 b.

Alternatively, the controller 20 may control the robot cleaner 100 so as to perform a low-speed backward traveling operation by causing the left spin mop 120 a and the right spin mop 120 b to be rotated inwards while causing the rolling mop 130 a to be rotated forwards at a fourth speed. Here, the absolute value of the fourth speed may be lower than the absolute value of the first speed. Consequently, although the backward propulsive force becomes higher than the forward propulsive force, thereby enabling a backward traveling operation, the speed of the robot cleaner 100 is decreased owing to the presence of the forward propulsive force.

Alternatively, the controller 20 may control the robot cleaner 100 so as to perform a low-speed forward traveling operation by causing the left spin mop 120 a and the right spin mop 120 b to be rotated inwards while causing the rolling mop 130 a to be rotated forwards at a higher speed than the third speed.

Referring to FIG. 13(a), when viewed from above, the left spin mop 120 a is rotated clockwise and the right spin mop 120 b is rotated counterclockwise; that is, the front spin mops 120 a and 120 b are rotated inwards so as to enable the robot cleaner 100 to perform a backward traveling operation.

In this case, the rolling mop 130 a may be rotated forwards so as to provide supplementary force in a forward direction, opposite the backward direction. Consequently, it is possible to decrease acceleration in a backward direction.

Referring to FIG. 13(b), when viewed from below, the left spin mop 120 a is rotated counterclockwise and the right spin mop 120 b is rotated clockwise; that is, the rear spin mops 120 a and 120 b are rotated inwards so as to enable the robot cleaner 100 to perform a backward traveling operation.

In this case, the rolling mop 130 a may be rotated forwards so as to provide supplementary force in a forward direction. Consequently, it is possible to decrease acceleration in a backward direction.

Thus, when both of the two front spin mops 120 a and 120 b and the rear rolling mop 130 a are rotated, the robot cleaner 100 is able to travel backwards at a lower speed than when only the two spin mops 120 a and 120 b are rotated. In other words, in order to increase cleaning performance, the robot cleaner 100 is able to travel backwards at a lower speed while maintaining the rotational speed of the spin mops 120 a and 120 b.

Furthermore, when the rotational speed (RPM) of the rolling mop 130 a is further increased while the mops are rotated in the above respective rotational directions, the robot cleaner 100 is able to perform a mopping operation by rotating the spin mops 120 a and 120 b and the rolling mop 130 a while standing in place (stationary operation).

In addition, when the rotational speed (RPM) of the rolling mop 130 a is further increased while the mops are rotated in the above rotational directions, the robot cleaner 100 is able to perform a mopping operation by rotating the spin mops 120 a and 120 b and the rolling mop 130 a while performing a forward traveling operation.

Specifically, it is possible not only to increase cleaning performance by increasing the rotational speeds of the spin mops 120 a and 120 b and the rolling mop 130 a but also to perform a concentrated cleaning operation of intensively performing a mopping operation on a certain area by decreasing the moving speed of the robot cleaner 100 or maintaining the robot cleaner 100 in the stationary state.

In a turning operation, the controller 20 may control a rotational direction by rotating at least one of the left spin mop 120 a and the right spin mop 120 b clockwise or counterclockwise and may control the turning extent of the robot cleaner 100 by rotating the rolling mop 130 a forwards or backwards.

Referring to FIG. 14(a), when viewed from above, the left spin mop 120 a and the right spin mop 120 b are rotated counterclockwise so as to enable the robot cleaner 100 to perform a right-turning operation.

In this case, the rolling mop 130 a may be rotated forwards so as to provide supplementary force in a forward direction. Consequently, the robot cleaner 100 may perform a turning operation with a larger turning radius.

Referring to FIG. 14(b), when viewed from below, the left spin mop 120 a and the right spin mop 120 b are rotated clockwise so as to enable the robot cleaner 100 to perform a right-turning operation.

In this case, the rolling mop 130 a may be rotated forwards so as to provide supplementary force in a forward direction. Consequently, it is possible to increase the turning radius of the robot cleaner 100.

Thus, when both of the two front spin mops 120 a and 120 b and the rear rolling mop 130 a are rotated, the robot cleaner 100 is able to turn right with a larger turning radius than when only the two spin mops 120 a and 120 b are rotated. It is possible to continuously move the center of the turning motion forwards while performing the turning operation.

Alternatively, when viewed from above, the controller 20 may control the robot cleaner 100 to perform a turning operation with a larger turning radius by rotating the left spin mop 120 a clockwise at a lower speed than the right spin mop 120 b while rotating the right spin mop 120 b counterclockwise or by rotating the rolling mop 130 b forwards while the left spin mop 120 a is stationary.

Alternatively, when viewed from above, the controller 20 may control the robot cleaner 100 to perform a turning operation with a larger turning radius by rotating the right spin mop 120 b clockwise at a lower speed than the left spin mop 120 a while rotating the left spin mop 120 a counterclockwise or by rotating the rolling mop 130 b forwards while the right spin mop 120 b is stationary.

Referring to FIG. 15(a), when viewed from above, the left spin mop 120 a and the right spin mop 120 b are rotated counterclockwise so as to enable the robot cleaner 100 to perform a right-turning operation.

In this case, the rolling mop 130 a may be rotated backwards so as to provide supplementary force in a backward direction. Consequently, the robot cleaner 100 may perform a turning operation with a smaller turning radius.

Referring to FIG. 15(b), when viewed from below, the left spin mop 120 a and the right spin mop 120 b are rotated clockwise so as to enable the robot cleaner 100 to perform a right-turning operation.

In this case, the rolling mop 130 a may be rotated backwards so as to provide supplementary force in a backward direction. Consequently, it is possible to decrease the turning radius of the robot cleaner 100.

Thus, when both of the two front spin mops 120 a and 120 b and the rear rolling mop 130 a are rotated, the robot cleaner 100 is able to turn right with a smaller turning radius than when only the two spin mops 120 a and 120 b are rotated. It is possible to continuously move the center of the turning motion backwards while performing the turning operation.

Alternatively, when viewed from above, the controller 20 may control the robot cleaner 100 to perform a turning operation with a smaller turning radius by rotating the left spin mop 120 a clockwise at a lower speed than the right spin mop 120 b while rotating the right spin mop 120 b counterclockwise or by rotating the rolling mop 130 b backwards while the left spin mop 120 a is stationary.

Alternatively, when viewed from above, the controller 20 may control the robot cleaner 100 to perform a turning operation with a smaller turning radius by rotating the right spin mop 120 b clockwise at a lower speed than the left spin mop 120 a while rotating the left spin mop 120 a counterclockwise or by rotating the rolling mop 130 b backwards while the right spin mop 120 b is stationary.

Referring to FIG. 16(a), when viewed from above, the left spin mop 120 a and the right spin mop 120 b are rotated clockwise so as to enable the robot cleaner 100 to perform a left-turning operation.

In this case, the rolling mop 130 a may be rotated forwards so as to provide supplementary force in a forward direction. Consequently, the robot cleaner 100 may perform a turning operation with a larger turning radius.

Referring to FIG. 16(b), when viewed from below, the left spin mop 120 a and the right spin mop 120 b are rotated counterclockwise so as to enable the robot cleaner 100 to perform a left-turning operation.

In this case, the rolling mop 130 a may be rotated forwards so as to provide supplementary force in a forward direction. Consequently, it is possible to increase the turning radius of the robot cleaner 100.

Thus, when both of the two front spin mops 120 a and 120 b and the rear rolling mop 130 a are rotated, the robot cleaner 100 is able to turn left with a larger turning radius than when only the two spin mops 120 a and 120 b are rotated. It is possible to continuously move the center of the turning motion forwards while performing the turning operation.

Alternatively, when viewed from above, the controller 20 may control the robot cleaner 100 to perform a turning operation with a larger turning radius by rotating the left spin mop 120 a counterclockwise at a lower speed than the right spin mop 120 b while rotating the right spin mop 120 b clockwise or by rotating the rolling mop 130 b forwards while the left spin mop 120 a is stationary.

Alternatively, when viewed from above, the controller 20 may control the robot cleaner 100 to perform a turning operation with a larger turning radius by rotating the right spin mop 120 b counterclockwise at a lower speed than the left spin mop 120 a while rotating the left spin mop 120 a clockwise or by rotating the rolling mop 130 b forwards while the right spin mop 120 b is stationary.

Referring to FIG. 17(a), when viewed from above, the left spin mop 120 a and the right spin mop 120 b are rotated clockwise so as to enable the robot cleaner 100 to perform a left-turning operation.

In this case, the rolling mop 130 a may be rotated backwards so as to provide supplementary force in a backward direction. Consequently, the robot cleaner 100 may perform a turning operation with a smaller turning radius.

Referring to FIG. 17(b), when viewed from below, the left spin mop 120 a and the right spin mop 120 b are rotated counterclockwise so as to enable the robot cleaner 100 to perform a left-turning operation.

In this case, the rolling mop 130 a may be rotated backwards so as to provide supplementary force in a backward direction. Consequently, it is possible to decrease the turning radius of the robot cleaner 100.

Thus, when both of the two front spin mops 120 a and 120 b and the rear rolling mop 130 a are rotated, the robot cleaner 100 is able to turn left with a smaller turning radius than when only the two spin mops 120 a and 120 b are rotated. It is possible to continuously move the center of the turning motion backwards while performing the turning operation.

Alternatively, when viewed from above, the controller 20 may control the robot cleaner 100 to perform a turning operation with a smaller turning radius by rotating the left spin mop 120 a counterclockwise at a lower speed than the right spin mop 120 b while rotating the right spin mop 120 b clockwise or by rotating the rolling mop 130 b backwards while the left spin mop 120 a is stationary.

Alternatively, when viewed from above, the controller 20 may control the robot cleaner 100 to perform a turning operation with a smaller turning radius by rotating the right spin mop 120 b counterclockwise at a lower speed than the left spin mop 120 a while rotating the left spin mop 120 a clockwise or by rotating the rolling mop 130 b backwards while the right spin mop 120 b is stationary.

The robot cleaner 100 according to an embodiment of the present invention may perform a traveling operation using movement resulting from the difference in drag force due to the difference in rotational speed and frictional force between the spin mops 120 a and 120 b, serving as front wheels, and the rolling mop 130 a, serving as a rear wheel.

Furthermore, when the spin mops 120 a and 120 b and the rolling mop 130 a are rotated so as to provide propulsive forces in the same direction, it is possible to perform a high-speed traveling operation by increasing a ratio of driving force of the rolling mop.

In addition, when the spin mops 120 a and 120 b and the rolling mop 130 a are rotated so as to attain the force equilibrium therebetween, the robot cleaner 100 stands in place while the spin mops 120 a and 120 b and the rolling mop 130 a concurrently slip, thereby enabling intensive cleaning at a specific location.

According to an embodiment of the present invention, the sensor unit 810 may include a position sensor 812 for detecting a position by receiving an external recognition signal, and the controller 20 may detect the position of the robot cleaner 100 based on the signal received from the position sensor 812.

The external recognition signal is a signal transmitted from a signal generator such as an externally located beacon, and the signal generator may include a plurality of signal generators, which are provided at a plurality of separate sites.

Accordingly, the position sensor 812 is able to receive a recognition signal transmitted from the signal generator located at different sites.

Referring to FIG. 18, the robot cleaner 100 may receive recognition signals from a signal generator, such as a UWB communication signal and a BLE signal, located at a plurality of sites a1, a2 and a3 through the position sensor 812.

The position sensor 812 may detect the position or direction of the robot cleaner 100 by performing a comparison operation among information such as the strength and direction of the recognition signal received from the signal generators located at the plurality of sites a1, a2 and a3 and the times at which the signals are received from the signal generators, information received at a previous site and information received at a current site.

The robot cleaner 100 according to the embodiment of present invention may detect a spatial position from a relative distance with respect to three or more signal generators located at a plurality of sites a1, a2 and a3.

For example, it is possible to detect a spatial position through a three-point positioning technology.

In this case, the controller 20 may calculate speed information via a comparison operation between input times and positions of the previous position information and the current position information based on the signal received at the position sensor 812. Furthermore, the controller 20 may control the rotation of the motor so as to follow a target trajectory by calculating the remaining distance and positional error with respect to the current site based on the position information.

The main controller 820 may control the rotation of the rolling mop 130 a in such a manner as to calculate speed information from a comparison operation performed on the input time and the position in the previously received position information and then to calculate input to the motor drive units 821 and 822 from calculation of the remaining distance and positional error with respect to the current site so as to follow a target trajectory based on the position information. Accordingly, it is possible for the robot cleaner 100 to reliably follow the target trajectory by virtue of the combined rolling and slipping motion.

For example, the position sensor 812 may be a UWB sensor employing a UWB communication signal.

The robot cleaner 100 is able to detect an absolute position in space in real time through a UWB sensor and to control traveling motion.

Furthermore, although it is difficult to estimate a travel distance and a current position through detection of the rotational speed of wheels owing to continuous slippage of the wheels, the present invention enables standing at a specific site, movement to a target point and travel to an area not cleaned, by virtue of the UWB sensor capable of detecting an indoor position in real time.

The sensor unit 810 may include an inertial measurement unit (IMU) 813. The inertial measurement unit 813 may include a gyro sensor 813 a, a geomagnetic sensor 813 b and an acceleration sensor 813 c. Alternatively, the sensor unit 810 may include the gyro sensor 813 a, the geomagnetic sensor 813 b and the acceleration sensor 813 c, which are independently provided.

Accordingly, the sensor unit 813 may measure a moving speed, a direction, a gravitational force and an acceleration of the robot cleaner 100.

Each of the gyro sensor 813 a and the acceleration sensor 813 c may be a triaxial sensor. The information collected from the gyro sensor 813 a may be roll, pitch and yaw information, and the information collected from the acceleration sensor 813 c may be x-axis acceleration, y-axis acceleration and z-axis acceleration information.

The inertial measurement unit sensor 813 is able to measure accelerations in the traveling direction, lateral direction and height direction and an angular speed of rolling, pitching and yaw. The controller 20 is able to perform calculation of a speed and a heading angle of the robot cleaner 100 by integrating an acceleration and an angular speed obtained by the inertial measurement unit sensor 813.

The rolling mop 130 a or the like of the robot cleaner 100 according to an embodiment of the present invention may be configured such that the ratio between rolling motion and slipping motion is continuously changed according to the changing state of frictional force.

The robot cleaner 100 according to an embodiment of the present invention may have a compensation control structure for controlling movement, which is able to change the RPM of the motor by controlling the output of the plurality of motor drive unit 821 and 822 according to variation in the acceleration and angular speed obtained by the inertial measurement unit sensor 813.

For example, the controller 20 may control the rotational speed of the left spin mop 120 a, the right spin mop 120 b and the rolling mop 130 a based on variation of acceleration and angular speed detected by the inertial measurement unit sensor 813.

The controller 20 is able to determine the current traveling state of the robot cleaner 100 based on predetermined information such as the heading angle of the robot cleaner 100 detected by the sensor unit 810.

Furthermore, the controller 20 is able to control stabilization of traveling motion through information obtained at the inertial measurement unit sensor 813.

Slipping extent and frictional force may vary according to the type and condition of the floor on which the robot cleaner 100 travels. The controller 20 is able to determine the traveling state of the robot cleaner 100, which varies according to the type and condition of the floor, through information obtained at the inertial measurement unit sensor 813, so as to perform compensation control.

FIG. 19 illustrates various condition of a floor that have an influence on frictional force.

FIG. 19(a) illustrates a linoleum sheet 1410, which is laid on a floor of a typical residential space. FIG. 19(b) illustrates a marble floor 1420, which is laid on the floor of a building lobby, a public facility or the like. FIG. 19(c) illustrates a coarse floor 1430. The coarse floor 1430 may be a floor made of a material having a coarse surface, such as a wood plate and a carpet.

The marble floor 1420 may be coarser, that is, may have greater frictional force, than the linoleum sheet 1410. Accordingly, when the robot cleaner 100 is controlled to be traveled with the same driving force, the actual traveling speed of the robot cleaner 100 on the marble floor 1420 may be higher than on the linoleum sheet 1410. The controller 20 may control the motors 124 and 137 d by respectively compensating the outputs of the motors 124 and 137 d using information, such as acceleration and speed, detected by the sensor unit 810.

The coarse floor 1430 may have a higher frictional force than the linoleum sheet 1410. Accordingly, when the robot cleaner 100 is controlled to travel with the same driving force, the actual traveling speed of the robot cleaner 100 on the coarse floor 1430 may be lower than on the linoleum sheet 1410. The controller 20 may control the motors 124 and 137 d by respectively compensating the outputs of the motors 124 and 137 d using information, such as acceleration and speed, detected by the sensor unit 810.

The sensor unit 810 may include the obstacle sensor 811 for detecting an obstacle in front of the robot cleaner 100, and the controller 20 may perform control so as to perform a skirting traveling operation with respect to a detected obstacle.

According to the present invention, the controller 20 is able to perform control of various traveling motions by combining motion of the front spin mops 120 a and 120 b with motion of the rear rolling mop 130 a.

Accordingly, the controller 20 may perform control so as to perform various skirting traveling operations according to an obstacle detected by the obstacle sensor 811.

The controller 20 may perform control so as to perform another skirting traveling operation based on the distance to an obstacle detected by the obstacle sensor 811.

For example, when the obstacle sensor 811 detects an obstacle, the controller 20 may perform control so as to perform a skirting traveling operation by rotating the rolling mop 130 a forwards or backwards, depending on the distance to an obstacle detected by the obstacle sensor 811, while rotating both the left spin mop 120 a and the right spin mop 120 b clockwise or counterclockwise.

In other words, as described with reference to FIGS. 14 to 17, since the controller 20 may control the turning radius of the robot cleaner 100, the robot cleaner 100 may perform a turning operation with a turning radius appropriate to the distance to an obstacle detected by the obstacle sensor 811, thereby skirting around the obstacle.

FIGS. 20 to 22 illustrate various examples of performing a skirting operation through turning traveling.

Referring to FIG. 20, during a traveling operation, the robot cleaner 100 may detect an obstacle 1900, which is located at a first distance d1 in a forward direction, by means of the obstacle sensor 811.

When the obstacle 1900 extends to the right side of the robot cleaner 100 or another obstacle is located on the right side of the robot cleaner 100, the controller 20 may control the robot cleaner 100 to turn right so as to skirt around the obstacle in consideration of an existing traveling path.

In this case, the controller 20 may determine whether the first distance d1 is sufficient for a larger turning radius BL, and may control the left spin mop 120 a and the right spin mop 120 b to be rotated clockwise when viewed from above while controlling the rolling mop 130 a to be rotated forwards, thereby causing the robot cleaner 100 to turn left with the larger turning radius BL.

Referring to FIG. 21, during a traveling operation, the robot cleaner 100 may detect an obstacle 1900, which is located at a second distance d2 in a forward direction, by means of the obstacle sensor 811.

When the obstacle 1900 extends to the right side of the robot cleaner 100 or another obstacle is located on the right side of the robot cleaner 100, the controller 20 may control the robot cleaner 100 to turn right so as to skirt around the obstacle in consideration of an existing traveling path.

In this case, the controller 20 may determine whether the second distance d2 is sufficient for a smaller turning radius SL, and may control the left spin mop 120 a and the right spin mop 120 b to be rotated clockwise when viewed from above while controlling the rolling mop 130 a to be rotated backwards, thereby causing the robot cleaner 100 to turn left at the smaller turning radius SL.

Referring to FIG. 22, during a traveling operation, the robot cleaner 100 may detect an obstacle 1900, which is located at a third distance d3 in a forward direction, by means of the obstacle sensor 811.

In this case, the controller 20 may determine whether the third distance d3 is sufficient for a smaller turning radius SL. If the robot cleaner 100 cannot turn at the smaller turning radius SL, the controller 20 may control the robot cleaner 100 to perform a backward traveling operation R1.

Alternatively, the controller 20 may control the robot cleaner 100 to turn left while performing a backward traveling operation R2 or to turn right while performing a backward operation R3 in consideration of the disposition of the obstacle 1900 and the existing traveling path.

According to at least one of the embodiments of the present invention, there is an advantage in that the robot cleaner performs a stable traveling operation using the pair of spin mops and a single rolling mop.

According to at least one of the embodiments of the present invention, it is possible to realize various traveling motions by combining rotational motion of the left and right spin mops with rotational motion of the rolling mop.

According to at least one of the embodiments of the present invention, the robot cleaner is able to perform a traveling operation suitable for the situation using various traveling motions.

According to at least one of the embodiments of the present invention, the robot cleaner is able to perform a mopping operation while standing in place.

The robot cleaner and the method of controlling the robot cleaner according to the present invention are not limited to the above-described embodiments, and all or some of the above embodiments may be selectively combined so as to realize various modifications.

While the present disclosure has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those of ordinary skill in the art that the present disclosure is not limited to the foregoing specific embodiments, and that various modifications may be made therein without departing from the spirit and scope of the present disclosure, and these modified embodiments should not be understood individually from the spirit and scope of the present disclosure.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. 

What is claimed is:
 1. A robot cleaner comprising: a first cleaning module including left and right spin mops configured to rotate clockwise or counterclockwise when viewed from above while being in contact with a floor; a second cleaning module including a rolling member configured to rotate clockwise or counterclockwise when viewed from a left side while being in contact with a floor, the rolling member being spaced apart from the left and right spin mops in an anteroposterior direction; and a controller for controlling rotational motion of the left and right spin mops and rotational motion of the rolling member.
 2. The robot cleaner according to claim 1, wherein the controller controls the rolling member to be accelerated or decelerated by changing a rotational direction and a rotational speed of the rolling member.
 3. The robot cleaner according to claim 1, wherein, upon performing a turning operation, the controller controls a rotational direction of the robot cleaner by rotating at least one of the left and right spin mops clockwise or counterclockwise, and controls a turning radius by rotating the rolling member forwards or backwards.
 4. The robot cleaner according to claim 1, wherein the controller controls the robot cleaner to perform a high-speed forward traveling operation by rotating the left and right spin mops outwards while rotating the rolling member forwards.
 5. The robot cleaner according to claim 1, wherein the controller controls the robot cleaner to stand in place by rotating the left and right spin mops outwards while rotating the rolling member backward at a first speed.
 6. The robot cleaner according to claim 1, wherein the controller controls the robot cleaner to perform a low-speed forward traveling operation by rotating the left and right spin mops outwards while rotating the rolling member backwards at a second speed.
 7. The robot cleaner according to claim 1, wherein the controller controls the robot cleaner to perform a high-speed backward traveling operation by rotating the left and right spin mops inwards while rotating the rolling member backwards.
 8. The robot cleaner according to claim 1, wherein the controller controls the robot cleaner to stand in place by rotating the left and right spin mops inward while rotating the rolling member forwards at a third speed.
 9. The robot cleaner according to claim 1, wherein the controller controls the robot cleaner to perform a low-speed backward traveling operation by rotating the left and right spin mops inwards while rotating the rolling member backwards at a fourth speed.
 10. The robot cleaner according to claim 1, further comprising a sensor unit including a plurality of sensors.
 11. The robot cleaner according to claim 10, wherein the sensor unit includes an inertial measurement unit (IMU) sensor, and wherein the controller controls rotational speeds of the left and right spin mops and the rolling member according to variation of acceleration and angular speed detected by the inertial measurement unit sensor.
 12. The robot cleaner according to claim 11, wherein the inertial measurement unit sensor includes a gyro sensor, a geomagnetic sensor and an acceleration sensor.
 13. The robot cleaner according to claim 10, wherein the sensor unit includes an obstacle sensor, and wherein, when the obstacle sensor detects an obstacle, the controller controls the robot cleaner to perform a skirting traveling operation by rotating the left and right spin mops clockwise or counterclockwise while rotating the rolling member forwards or backwards according to a distance to the obstacle detected by the obstacle sensor.
 14. The robot cleaner according to claim 10, wherein the sensor unit includes a position sensor for receiving an external recognition signal to detect a position of the robot cleaner, and wherein the controller calculates speed information based on a receipt time of the recognition signal at the position sensor, and then controls rotation of the motor by estimating a target trajectory from calculation of a remaining distance and positional error with respect to the target trajectory and the current site, based on position information of the position sensor.
 15. The robot cleaner according to claim 14, wherein the position sensor is an ultra-wideband (UWB) sensor. 